Organic Pest Control and IPM

Master Gardeners of Montgomery County

Diyan Rahaman

Who are we?

Outline

Why are chemicals so bad?

Integrated Pest Management

Organic Principles

Strategies – Healthy Plants

– Environmental Enhancements

– Control Methods

Summary

References

Questions

Effects of Chemicals

Resistance

– Naturally resistant individuals in a pest population are able to survive pesticide

treatments. The survivors pass on the resistance trait to their offspring. The

result is a much higher percentage of the pest population resistant to a pesticide.

Resurgence

– Pesticides often kill off natural enemies along with the pest. With their natural

enemies eliminated, there is little to prevent recovered pest populations from

exploding to higher, more damaging numbers than existed before pesticides

were applied. Additional chemical pesticide treatments only repeat this cycle.

Secondary Pests

– Some potential pests that are normally kept under good control by natural

enemies become actual pests after their natural enemies are destroyed by

pesticides. Mite outbreaks after pesticide applications are a classic example.

Residues

– Only a minute portion of any pesticide application contacts the target organism.

The remainder may degrade harmlessly, but too often water, wind, and soil

carries pesticides to non-target areas and organisms, affecting the health of

human and wildlife populations.

Pesticide Resistance

Before After

Resistant individual Susceptible individual

Pest Resurgence

Before After

Aphid (pest) Lacewing larva (predator)

Secondary Outbreak

Before After

Pest A: aphid Predator A: lacewing larva

Pest B: spider mite Predator B: predatory mite

Integrated Pest Management (IPM)

Preventing plant and pest problems.

Identifying pests, beneficials and their ecology.

Regular monitoring of plants, pests, beneficials and practices that affect them.

Taking action if necessary using an integrated approach utilizing physical, mechanical, cultural, biological and chemical controls.

Evaluating action and continuing to monitor.

Steps

Scouting for pests, including weeds, diseases, and insects, is a key component of integrated pest management. (Source: USDA Natural Resources Conservation Service)

Organic Principles

A Dynamic Eco-system

Has a high diversity of plants and animals both above and below the ground.

Greater diversity produces greater stability within the system and minimizes pest problems.

Factors Affecting Outbreaks

pest

plant place

Strengthen the plant by using resistant cultivars and building healthy soil.

Make the place (environment) friendlier to plants or less friendly to pests.

Reduce pest load by crop rotation, diversity and sanitation.

Problems are minimized when you:

Strategies

Minimal Pest Damage

Growing healthy plants

Select well adapted varieties

Build healthy soil

Enhance environment

Maintain good cultural

practices

Habitat conservation

and enhancement

Reduce pests

Crop rotation, diversity and

sanitation

Control actions

Defense Mechanisms

Plants are not passive in the face of attack by insects, nematodes, or diseases caused by fungi and bacteria. Genes activated when plants are attacked or stimulated by organisms produce chemicals that – Slow insect feeding.

– Attract beneficial organisms.

– Produce chemicals that provide a degree of resistance to pathogenic bacteria, fungi, and viruses.

Resistant Cultivars

Cultivars should be

resistant to major

pests/diseases.

Cultivars should be

appropriate for the area.

Cultivars should be

commercially available.

Disease and Pest Resistance Key V = Verticillium Wilt F = Fusarium Wilt Race 1 N = Nematodes ASC = Alternaria Stem Canker ST = Stemphylium (gray leaf spot)

Healthy Soil

Add Organic matter

Increased biological activity and diversity

Decomposition Reduced soilborne diseases, parasitic nematodes

Aggregation increased

Pore structure improved

Improved tilth and water storage

Humus and other growth-promoting substances

Nutrients released

Harmful substances detoxified

HEALTHY PLANTS

Improving Soil Health

Growing cover

crops.

Reducing tillage.

Avoiding soil

compaction.

Applying organic

amendments.

Cover Crops

Add specific nutrients.

Increase level of

organic matter.

Improve soil structure.

Increase water and

nutrient holding

capacity of the soil.

Prevent erosion.

Reduce weeds.

Reduce Tillage and Compaction

Low/no till reduces

energy and labor.

Reduces soil compaction.

Residue cover protects

soil from erosion.

Allows for greater

moisture retention.

Creates a favorable

ecosystem underground.

Compost and Amendments

Use of compost is beneficial to build soil organic matter, add nutrients to the soil and retain water.

Compost tea is the liquid extract from steeping compost in water and is used as a fertilizer but also to treat fungal diseases.

Cultural Practices

Good Drainage

Good Airflow

Proper Watering

Habitat Conservation and Enhancement

Reduction of pest habitat

– Reduce/alter overwintering

pest sites.

Augmentation of

beneficial habitat

– Insectary establishment.

– Consider both permanent

plantings such as

hedgerows and annual

options.

Reduce Pest Populations

Crop Rotation

Crop Diversity

Sanitation

Crop Rotation

Potatoes

Squash

Root crops

Beans Tomatoes

English peas

Cabbage family

Sweet corn

Leaf crops

Fruit crops

Root crops

Legumes

Four Year Cycle Eight Year Cycle

Companion Planting

The benefits of increasing

diversity by companion

planting are

– Trap cropping.

– Symbiotic nitrogen fixation.

– Biochemical pest suppression.

– Physical spatial interaction.

– Beneficial habitat.

– Security through diversity.

Sanitation

Immediately remove

diseased plants and plant

material from the area where

healthy plants are growing.

Destroy any nearby weedy

habitats that shelter pests.

Clean accumulated weed

seeds from equipment before

using again.

Sterilize pruning tools.

Controls – Physical/Mechanical

Hand picking

Row covers

Bagging

Controls - Biological Controls

Conservation and Enhancement – Is used to provide optimal

conditions for the survival of native beneficials.

Augmentation – Supplements the numbers

of naturally occurring beneficials with releases.

Importation – The deliberate introduction

and establishment of exotic natural enemies to combat exotic pests.

Importation

Conservation Augmentation

Biological Control

Beneficial Insects – Lady Bugs

Larvae and adults eat: – Aphids, mealy bugs, mites,

soft scale and eggs of insect pests.

In plants of the carrot family – fennel, dill, Queen Anne’s lace.

Also yarrow and sunflowers.

Clumping grasses are excellent habitats for overwintering ladybugs.

What do they eat?

Where do they live?

Beneficial Insects – Lacewings

The larvae eat softbodied insects including aphids, thrips, mealy bugs, soft scale, worms, and mites.

The adults eat pollen and nectar.

In plants of the carrot family – fennel, dill, Queen Anne’s lace.

Also yarrow, sunflowers, buckwheat, corn, amaranth, alyssum.

What do they eat?

Where do they live?

Beneficial Insects – Bigeyed Bugs

Nymphs and adults eat many insects including: – Aphids, Mites, Thrips,

Worms, Flea beetles and Insect eggs

Cool season cover crops (clover) and common knotweed.

What do they eat?

Where do they live?

Beneficial Insects – Pirate Bugs

Nymphs and adults eat: – Thrips

– Mites

– Leafhoppers

– Small worms

– Insect eggs

In plants of the carrot family – fennel, dill, Queen Anne’s

lace.

Also yarrow, sunflowers, buckwheat, alyssum, alfalfa, corn, clover, and vetch.

What do they eat?

Where do they live?

Beneficial Insects – Assassin Bugs

Nymphs and adults eat:

– Many insects including

large insects and worms.

In permanent plantings

such as hedgerows,

which provide shelter

and food.

What do they eat?

Where do they live?

Beneficial Insects – Braconid Wasp

Larvae are parasites of:

– Armyworm, cabbageworm,

codling moth, gypsy moth,

European corn borer, beetle

larvae, flies, aphid,

caterpillars, other insects.

Nectar plants with small flowers

(caraway, dill, parsley, Queen

Anne’s lace, fennel, mustard,

white clover, tansy, yarrow),

sunflower, hairy vetch, buckwheat,

cowpea, common knotweed,

crocuses, spearmint.

What do they eat?

Where do they live?

Beneficial Micro-organisms

Organism Description

Bacillus popilliae Is a bacteria that is commonly known as milky spore and primarily affects Japanese beetles.

Bacillus thuringiensis Is brewed from a soil dwelling bacterium and owes its toxicity to a protein referred to as Bt.

Nematodes Are little worms that eat insects from the inside out and are most effective at controlling insects that spend a portion of their time living in the soil.

Chemical Controls

Chemical pesticides are to be used only as a last resort.

Conventional chemicals – include synthetic, broad-spectrum pesticides that

often have unwanted side effects – harming other species or polluting the environment.

Biorationals – are more specifically toxic to or disruptive of target

pests. Naturally derived or synthesized, they include growth regulators, microbial toxins, anti-feeding agents, pest-smothering oils, and disruption pheromones that confuse insects and reduce their reproductive success.

Botanicals

Method Description

Neem Comes from the tropical tree Azadirachta indica, and works in two ways – as a growth regulator and as a repellent.

Pyrethrum Comes from a species of chrysanthemum, Chrysanthemum cineraria folium, and acts as a nerve toxin.

Capsaicin Is a hot pepper solution which contains the chemical capsaicin and can be used to repel insects.

Citrus oil Contains the compound limonene and linalool, both of which act as nerve toxins in insects.

Garlic The active ingredient in sprays made with garlic include the chemicals diallyl disulfide and diallyl trisulfide.

Contact/Barrier

Method Description

Oils Dormant oils, usually applied in winter, work as an insecticide by suffocating insects that are trying to over winter on plants.

Soaps Insecticidal soaps work to control insects by removing their waxy cuticle, causing them to desiccate and die.

Diatomaceous earth

Is made up of the fossilized skeletons of microscopic organisms called diatoms.

Kaolin Is a form of clay, composed primarily of silicon and aluminum, and works by creating a physical barrier around the plant.

Conventional vs Organic Approaches

Sanitation, timing and crop rotation

Above ground beneficial habitat and healthy soil

Plant cultivars appropriate to the

environmental and pest pressures

Monitoring of Pests

Mechanical

Biological

Chemical

Monitoring of Beneficials

REA

CTI

VE

PR

OA

CTI

VE

ORGANIC CONVENTIONAL

Summary

Control pest populations through cultural practices.

Enhance pest-predator balances using plant diversity.

Use biodegradable pesticides that have low toxicity to beneficial insects, fish, birds, and mammals.

References

General and Organic

HGIC. 2008. The Maryland Master Gardener Handbook.

Gillman, Jeff. 2008. The Truth About Organic Gardening.

Ellis and Bradley Eds. 1996. The Organic Gardeners Handbook of Natural Insect and Disease Control.

M L Flint, S Dreistadt, 2000. Natural Enemies Handbook.

Insects

Cranshaw, Whitney.

2004. Garden Insects of

North America.

Gill, Stanton. 2006. Pests

and Diseases of

Herbaceous perennials.

Johnson and Lyon. 1991.

Insects that Feed on

Trees and Shrubs.

Questions?

For further questions:

Call us at: 301-590-9650

Email address:

mgmont@umd.edu

See our fact sheets:

www.hgic.umd.edu